This invention relates to a method and an apparatus for measuring the wheel and tire (hereinafter any reference to wheel means wheel and tire) alignment of motor vehicles, and more particularly relates to a method and an apparatus for measuring toe-in and/or camber of wheels of motor vehicles.
The measuring method and apparatus of the present invention can be effectively employed in an inspection line of a vehicle assembling or repairing factory, where toe-in and/or camber of wheels should be measured.
In this disclosure the term "toe-in" means toe-in or toe-out.
In the prior art, toe-in of wheels of a vehicle has been measured by using a dynamic toe tester. Front wheels are placed on the dynamic toe tester and rotated by a rotating drum, and the side force (i.e. the force by which the drum is moved in the transverse direction) of both the left and right wheels is measured. Then the valve of toe-in is determined by a calculating operation. However, according to the conventional method, it has been impossible to separate the left and right values of the toe-in with respect to the longitudinal center line of the vehicle. In other words, the horizontal directions of the front wheels with respect to the horizontal direction of the vehicle cannot be determined. Therefore, even if the value of toe-in is determined correctly, and the front wheels are situated for the straight forward direction, the steering wheel is often mounted at an inclined angle. In addition, in the case of a front engine and front drive vehicle, or a four wheel independent suspension type vehicle, toe-in of the rear wheels should be established. In the conventional art, no measuring apparatus has been found, by which apparatus toe-in of rear wheels is simultaneously measured with toe-in of front wheels.
An object of the present invention is to provide a method and an apparatus for measuring toe-in of vehicles, by which toe-in of front wheels and toe-in of rear wheels are simultaneously measured and the value of the toe-in can be divided into the right and the left with respect to the longitudinal center line of the vehicle.
Another object of the present invention is to provide a method and an apparatus for measuring, at the same time, toe-in and camber of a wheels of vehicle.
A further object of the present invention is to provide a method and an apparatus for accurately measuring toe-in and camber of wheels of a vehicle with a means having a simple construction.
According to an aspect of the essential features of the present invention, an apparatus for measuring the wheel alignment of motor vehicles comprises at least a pair of measuring units, each unit comprising a plate member, means for supporting and bringing said plate member in contact with the outer side face of one of a pair of front or rear wheels of a vehicle, and sensor means for detecting the inclination of said plate member in the vertical level, which is perpendicular to the floor surface on which said vehicle is placed, and/or detecting the direction of said plate member in the horizontal level, which is parallel to said floor surface.
According to another aspect of the essential features of the present invention, a method for measuring the wheel alignment of motor vehicles comprises the steps of: bringing at least a pair of sensor plates into contact with the outer side face of a pair of wheels, respectively, detecting the inclination of said plate members in a predetermined vertical level and/or detecting the direction of said plate members in a predetermined horizontal level, and determining toe-in and/or the angle of camber of the wheel or wheels.